
S e r i e s
Standard Application
Cin
Cout= Optional 1μH input choke
L1
= Required 2400μF electrolytic
32 AMP HIGH-PERFORMANCE
“SLEDGE HAMMER” PROGRAMMABLE ISR
P T 7 7 7 0
The PT7770 is a new series of
high-performance, 32 Amp Inte-
grated Switching Regulators (ISRs)
housed in a 27-pin SIP package.
The 32A capability allows easy
integration of the latest high-speed,
low-voltage μPs, ASICs, DSPs, and
bus drivers into existing 5V systems.
The output voltage of the
PT7770 can be easily programmed
from 1.3V to 3.5V with a 5 bit input
compatible with Intel’s Pentium
Pro Processor. A differential
remote sense is also provided
which automatically compensates
for any voltage drop from the ISR
to the load.
2400μF of output capacitance
are required for proper operation.
For STBY* pin; open = output enabled;
ground = output disabled.
Pin-Out Information
Pin
Function
1
VID0
2
VID1
3
VID2
4
VID3
5
STBY*- Stand-by
6
VID4
7
V
in
8
V
in
9
V
in
10
V
in
11
V
in
12
Remote Sense Gnd
13
GND
PT7770
7 - 11
13 - 19
20 - 25
27
V
IN
GND
1μH
GND
V
OUT
C
OUT
+
C
IN
+
12
26
1
L1
SYNC OUT
LOAD
REMOTE SENSE (+)
REMOTE SENSE (-)
VID1
PROGRAMMING PINS
VID0
2
3
4
STBY*
5
6
For assistance or to order, call
(800) 531-5782
2
Power Trends, Inc.
27715 Diehl Road, Warrenville, IL 60555
(800) 531-5782
Fax: (630) 393-6902
http://www.powertrends.com
Pin
14
15
16
17
18
19
20
21
22
23
24
25
26
27
Function
GND
GND
GND
GND
GND
GND
V
out
V
out
V
out
V
out
V
out
V
out
Remote Sense V
out
Sync Out
Specifications
Characteristics
(T
a
= 25°C unless noted)
Output Current
PT7770 SERIES
Min
0.1
(1)
0.1
(1)
4.5
(2)
Symbols
I
o
Conditions
T
a
=
+60°C, 200 LFM, pkg N
T
a
=
+25°C, natural convection
0.1A
≤
I
o
≤
32A
V
= +5V, I
= 32A
0°C
≤
T
a
≤
+55°C
4.5V
≤
V
in
≤
5.5V, I
o
= 32A
V
in
= +5V, 0.1
≤
I
o
≤
32A
V
in
= +5V, I
o
= 32A
I
o
step between 16A and 32A
V
o
over/undershoot
V
in
= +5V, I
o
= 20A, V
o
= 3.3V
4.5V
≤
V
in
≤
5.5V
0.1A
≤
I
o
≤
32A
Typ
—
—
—
Max
32
26
5.5
Units
A
A
V
Input Voltage Range
Output Voltage Tolerance
V
in
V
o
V
o
-0.03
—
V
o
+0.03
V
Line Regulation
Load Regulation
V
o
Ripple/Noise pk-pk
Transient Response
with C
out
= 2400μF
Efficiency
Switching Frequency
Reg
line
Reg
load
V
n
t
tr
V
os
η
o
—
—
—
—
—
—
±10
±10
50
100
200
90
—
—
—
—
—
—
mV
mV
mV
μSec
mV
%
650
700
750
kHz
Absolute Maximum
Operating Temperature Range
Recommended Operating
Temperature Range
Storage Temperature
Weight
T
a
—
0
—
+85
°C
T
a
Forced Air Flow = 200 LFM
Over V
in and
I
o
Ranges
—
Vertical/Horizontal
0
—
+65
°C
T
s
—
-40
—
—
53/66
+125
—
°C
grams
(1) ISR-will operate down to no load with reduced specifications. Please note that this product is not short-circuit protected.
(2) The minimum input voltage is 4.5V or V
out
+1.2V, whichever is greater.
Output Capacitors:
The PT7770 series requires a minimum output capacitance of 2400μF for proper operation. Do not use Oscon type capacitors.
The maximum allowable output capacitance is 30,000μF.
Input Filter:
An input filter is optional for most applications. The input inductor must be sized to handle 32ADC with a typical value of 1μH.
The input capacitance must be rated for a minimum of 2.6Arms of ripple current. For transient or dynamic load applications, additional
capacitance may be required.
Application Notes
Mechanical Outline
Product Selector Guide
Revised 5/15/98